package com.lagou.rpc.client;

import com.lagou.common.util.*;
import com.lagou.common.zk.ServiceCenter;
import com.lagou.rpc.client.handler.UserClientHandler;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.UUID;
import java.util.concurrent.ExecutorService;

import static java.util.concurrent.Executors.newFixedThreadPool;

public class RpcConsumer {

    private static RpcService currentService;

    // 创建线程池对象
    private static ExecutorService executor = newFixedThreadPool(Runtime.getRuntime().availableProcessors());

    private static UserClientHandler userClientHandler;

    // 1.创建一个代理对象
    public Object createProxy(final Class<?> serviceClass) {

        // 借助JDK动态代理生成代理对象
        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), new Class<?>[]{serviceClass}, new InvocationHandler() {

            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                //（1）调用初始化netty客户端的方法
//                if (userClientHandler == null) {
                    initClient();
//                }

                // 设置参数
                RpcRequest request = new RpcRequest();
                request.setRequestId(UUID.randomUUID().toString());
                request.setClassName(serviceClass.getName());
                request.setMethodName(method.getName());
                request.setParameterTypes(Arrays.stream(args).map(Object::getClass).toArray(Class[]::new));
                request.setParameters(args);

                userClientHandler.setRpcRequest(request);
                userClientHandler.setRpcService(currentService);

                // 去服务端请求数据
                return executor.submit(userClientHandler).get();
            }
        });
    }

    // 2.初始化netty客户端
    public static void initClient() throws Exception {

        userClientHandler = new UserClientHandler();
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(group)
                .channel(NioSocketChannel.class)
                .option(ChannelOption.TCP_NODELAY, true)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ChannelPipeline pipeline = ch.pipeline();
                        pipeline.addLast(new RpcEncoder(RpcRequest.class, new JSONSerializer()));
                        pipeline.addLast(new StringDecoder());
                        pipeline.addLast(userClientHandler);
                    }
                });

        currentService = ServiceCenter.nextService();
        bootstrap.connect(currentService.getHostname(), currentService.getPort()).sync();
    }
}
